Man kills himself after throwing explosive device at a closed US embassy in Montenegro

Police guard the entrance to the United States embassy building in Podgorica, Montenegro, February 22, 2018. Stevo Vasiljevic/Reuters

The US Embassy in Montenegro cautioned people that there is an "active security situation."

The embassy's statement comes amid reports of a grenade attack on Wednesday night.

The US embassy in Montenegro cautioned people that there is an "active security situation" in the capital of Podgorica on Wednesday night after a man threw an explosive device, the State Department said in a New York Times report.

A man reportedly threw the explosive device at the building, which was closed for the night, and killed only himself and injured no others, The Times reported.

Montenegro's government said in two tweets that the man "probably" threw a hand grenade before he "committed suicide with an explosive device."

The embassy building did not sustain damage during the attack and no other explosives were found, according to Steve Goldstein, the State Department's under secretary for public diplomacy and public affairs.

No motive was discovered as of Wednesday night.

The embassy said in its statement to "avoid the embassy until further notice." Montenegro became the 29th country to join NATO last year.